<h4>Tool</h4><table border="0"><tr><td valign="top"><b>Name</b></td><td valign="top">Downslope Area</td></tr><tr><td valign="top"><b>ID</b></td><td valign="top">5</td></tr><tr><td valign="top"><b>Author</b></td><td valign="top">(c) 2001 by O.Conrad</td></tr><tr><td valign="top"><b>Specification</b></td><td valign="top">grid, interactive</td></tr></table><hr><h4>Description</h4>This interactive tool allows you to specify source cells (with a left mouse click), for which the downslope area shall be identified. For the 'Deterministic Infinity' and 'Multiple Flow Direction' algorithms, which are able to simulate flow divergence, the result will give the percentage of the source cell's flow that drains through each cell.

References:

Deterministic 8
- O'Callaghan, J.F. / Mark, D.M. (1984):
    'The extraction of drainage networks from digital elevation data',
    Computer Vision, Graphics and Image Processing, 28:323-344

Rho 8:
- Fairfield, J. / Leymarie, P. (1991):
    'Drainage networks from grid digital elevation models',
    Water Resources Research, 27:709-717

Braunschweiger Reliefmodell:
- Bauer, J. / Rohdenburg, H. / Bork, H.-R. (1985):
    'Ein Digitales Reliefmodell als Vorraussetzung fuer ein deterministisches Modell der Wasser- und Stoff-Fluesse',
    Landschaftsgenese und Landschaftsoekologie, H.10, Parameteraufbereitung fuer deterministische Gebiets-Wassermodelle,
    Grundlagenarbeiten zu Analyse von Agrar-Oekosystemen, (Eds.: Bork, H.-R. / Rohdenburg, H.), p.1-15

Deterministic Infinity:
- Tarboton, D.G. (1997):
    'A new method for the determination of flow directions and upslope areas in grid digital elevation models',
    Water Resources Research, Vol.33, No.2, p.309-319

Multiple Flow Direction:
- Freeman, G.T. (1991):
    'Calculating catchment area with divergent flow based on a regular grid',
    Computers and Geosciences, 17:413-22

- Quinn, P.F. / Beven, K.J. / Chevallier, P. / Planchon, O. (1991):
    'The prediction of hillslope flow paths for distributed hydrological modelling using digital terrain models',
    Hydrological Processes, 5:59-79

Kinematic Routing Algorithm:
- Lea, N.L. (1992):
    'An aspect driven kinematic routing algorithm',
    in: Parsons, A.J., Abrahams, A.D. (Eds.), 'Overland Flow: hydraulics and erosion mechanics', London, 147-175

DEMON:
- Costa-Cabral, M. / Burges, S.J. (1994):
    'Digital Elevation Model Networks (DEMON): a model of flow over hillslopes for computation of contributing and dispersal areas',
    Water Resources Research, 30:1681-1692

<hr><h4>Parameters</h4><table border="1" width="100%" valign="top" cellpadding="5" rules="all"><tr><th>Name</th><th>Type</th><th>Identifier</th><th>Description</th><th>Constraints</th></tr>
<tr><th colspan="5">Input</th></tr><tr><td>Elevation </td><td>Grid (input)</td><td>ELEVATION</td><td></td><td></td></tr><tr><td>Sink Routes (*)</td><td>Grid (optional input)</td><td>SINKROUTE</td><td></td><td></td></tr><tr><th colspan="5">Output</th></tr><tr><td>Downslope Area</td><td>Grid (output)</td><td>AREA</td><td></td><td></td></tr><tr><th colspan="5">Options</th></tr><tr><td>Method</td><td>Choice</td><td>METHOD</td><td></td><td>Available Choices:
[0] Deterministic 8
[1] Rho 8
[2] Braunschweiger Reliefmodell
[3] Deterministic Infinity
[4] Multiple Flow Direction
[5] Multiple Triangular Flow Directon
[6] Multiple Maximum Downslope Gradient Based Flow Directon
[7] Kinematic Routing Algorithm
[8] DEMON
Default: 4</td></tr><tr><td>Convergence</td><td>Floating point</td><td>CONVERG</td><td>Convergence factor for Multiple Flow Direction algorithm</td><td>Minimum: 0.001000
Default: 1.100000</td></tr></table>(*) <i>optional</i>